Gas turbine



Oct. -13, 1931 c.v LoRENzEN GAS TURBINE Filed May 16, 1930 v y I WEA/TOR Cams-twv Lon-Naw l O/K @M l umu.

Patented Oct. 13, 1931' UNITED STATES PATENT oFFlcE CHRISTIAN LORNZEN,OF BERIJN-TREPTOW, GERMANY, ASSIGNOB, T0 BENDIX AVIA- TION CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE GAS TURCBINE Application iled May 16, 1930, Serial No. 453,009, and in Germany .Tune 7, y192'?.

My present invention relates to gas turbines, and has for its special object to 1 mprove the construction of those parts which are exposed at the same time to high pressure [5 and high temperature. Considerable dllicult-ies have been experienced 1n practlce with reference to such parts, and particularly the combustion chamber in which the driving gas is produced, the nozzles through j@ which such gas is discharged against the rotor of the turbine, and the conduit through which the gas is conveyed from said combustion chamber or producer to such nozzles. It has b'een proposed to surround said parts :is with a jacket of refractory material capable of withstanding high temperatures and having heat-insulating properties, so as to prevent or minimize the outward propagation of the heat, and according to such proposiao tion, the jacket (which is not particularly resistant to pressure) Was to be encased in an outer wall of sheet metal, well able to resist pressure, but not so well adapted to resist high temperatures. The purpose was to have the refractory jacket keep the heat from reaching the sheet metal shell, while the latter was expected to furnish the requisite resistance against pressure. It was found, however, that the inevitable temperarefractory jacket material, and through these cracks the high temperature would reach the sheet metal shell, which would thus be deprived, in a large measure, of the protective ell'ectexerted by the refractory jacket as long as the latter remained undamaged, that is to say, imperforate. The strength of the metal shell would thenbe reduced materially by such exposure of .high temperatures. Another expedient proposed vfor dealing with the difficulty' mentioned above, consisted in causing a fluid cooling mediuml (for instance air or other gases, or liquids) to circulate or iiow through a jacket surrounding the path of the hot driving gas. This procedure, how- I the vdriving gas as to reduce very materially the degree of eliiciency with which the turbine could be operated.

C0 To overcome these defects, I have devised ture variations would produce cracks in the ever, abstracted so much heat energy from a construction according to which the parts constituting the path of the driving gas are made of refractory material, and are surrounded by a jacket which contains two kinds of materials, viz. one material, of granular structure, insulating against heat, and a fluidmaterial under pressure, for instance compressed air or gas.

By this novel arrangement l secure a douas compared with the parts forming the walls.

of the path through which the hot driving medium courses.. l do not abstract heat by a continuous flow of acooling fluid, as in some prior constructions, but the jacket space Y has no outlet, and is closed so as to contain permanently a stagnant body of gas, the only purpose of which is to exert a pressure counteracting that of the driving medium and thus to relieve the Walls of the hot driving gas path, of excessive pressure.

In large-size installations, the walls forming the path of the driving gas may consist of elements, for instance segments or pipe sections, overlapping in such a manner as to permit longitudinal expansion or contraction, or such elements may simply be in loose Contact at their meeting portions. joints are not essential, since the pressure is preferably the same on the outside as on the inside. The granular material which ills the jacket space will admit of uneven expansion when heated more or less strongly. Should nevertheless cracks develop in the walls forming the path of the hot driving gas, this will have no serious consequences in my improved construction, since the gas will have practically no tendency to escape into the jacket through such cracks.

Tight The stator blades or nozzles are preferably made of metal, for the sake of more convenient manufacture, and it is therefore desirstance, such expansion may take place in an annular nozzle conduit located in the immediate vicinity of the stator blades or noz- Some diiiculty ma be expected in obtaining tight joints at t e points where the refractory material, exposed to high pressure, is in contact with the metal stator blades or nozzles, exposed to a lower pressure. According to my invention, this diiculty is overcome by .providing flanges located within the jacket s ace and forced uniformly against the joint by the static pressure prevailing in4 said space.

To maintain the proper pressure in the jacket space, I preferto connect said space with the delivery side of a compressor associated with the turbine and furnishing the pressure for the interior of the path through which the hot aseous driving medium travels to the turbine. This connectionfmay be made either at the outlet of the compressor, or at any other suitable point of the delivery conduit. It is to be understood that there is no flow in such connection, but only a transfer of pressure.

A. satisfactory and preferred embodiment of my invention is shown, as an exainle, in

theaccompanying drawings, in whic Fig. 1 illustrates such embodiment` in vertical section, and Fig. 2 shows a detail, upon an enlar ed scale.

he gas turbine 1 (of any suitable construction) has a direct drive connection with the air compressor 2 (likewise of any suitable construction) which delivers air for."

supporting combustion, to the combustion chamber 3, provided with fuel inlets or burners 14 of any appropriate type. Hot combustion gases produced in the chamber 3 are driven, under the pressure exerted b the compressor 2, through the pipe or con uit 4 and into the annular conduit 5.' The gases then pass through the stator nozzles or blades indicated at 6, and impinge upon the rotor blades 7 of Vthe turbine, whereupon the reach the outlet channel 8,

'lyhe parts exposed to high pressure and high temperature, that is to say, the com.-

bustion .c amber 3 and the conduits 4, 5 are made of iirebrick, carborundum, special tem'- A plerature-resistingsteel, or other material reactory to heat. At a' suitable distance, these parts are surrounded by a metal shell 15, resistant to pressure. The intervening pressure of the compressor. This delivery pressure will also prevail in the combustion chamber 3 and the conduits 4,v 5.

-The conduit 5 may be provided with an annular expansion outlet 5, that is to say, an outlet flaring toward the stator nozzles 6,

so that the gases during their passage through said outlet 5" will be cooled by expansion,

and also reduced in pressure, to a point where their temperature and pressure will not affect the nozzles 6 injuriously.

j At the outlet end of the conduit, and still within the jacket space 10, the refractory material of which said conduit is made, is provided with a flange 12 fitted tightly against the metal nozzles 6 and against the metal casing 13 of the turbine- 1. The compressor in the jacket space 10,

pressure prevailin will thus hold the ange 12 in tight engagement with said metal parts. A similar flange 12. may be located atthe air inlet of the combustion chamber 3 to preserve, in the saine manner, a tight joint between the refractory material of saidchamber and the metal of the surrounding shell 15, at the outlet of the delivery lpipe coming from the compressor 2.

F1 2 illustrates the details of an expansion joint which I may employ in the conduit 4 when the arts are of relativel considerable dimensions. The two conduit Vsections havev nested portions 16 of reduced thickness which may slide lengthwise upon each other when the conduitexpands or contracts. The gap 18 which generally remains between the extremit of one conduit section and the shoulder on t e ,other conduit section,

is covered by a ring 17 wide enough to bridge said gap in all positions of said sections, thus to revent the granular material 9 from entering the ap 18 and interfering'with the longitudine. movement of vthe overlapping4 endsof the conduit sections.

' Various modifications may be made with` out departing from the nature of my invention as set forth inthe appended claims.

Iclaim:l 1. In combination, a conduit made of heatsurroundin said conduit vat a distance, and means for eepincr said jacket filled with a stagnant gaseous uid under pressure.

,12s resisting material, for conveyin a hot gaseousdriving medium to a place o use, a jacket `ist 2. A device according to claim 1, in which the jacket, in addition to the stagnant gaseous fluid under pressure, contains a loose filling of refractory material.

3. In combination, a refractory combustion chamber for producing hot gases under pressure, a conduit made of refractory material, for conveying said hot gases to a place of use, a jacket surrounding said combustion chamber and said conduit at a distance, and means for keeping said jacket filled with a stagnant gaseous Huid under pressure.

4. In combination, a refractory combustion chamber for producing hot gases under pressure, a conduit made of refractory material, for conveying said hot gases to a place of use, a jacket surrounding said combustion A chamberV and said conduit at a distance, means for keeping said jacket filled with a stagnant gaseous fluid under pressure, and a loose filling of refractory material in said jacket5 5. In combination with a turbine, a combustion chamber for producing hot gases under pressure, anl air compressor driven by said turbine and arranged to deliver air un- .nection from the delive pressure to said chamber, the latter having, within the jacket, a angelocated at the a1r inlet and forming a jointwith the delivery connection of the air compressor, and a conv side of the compressor to said jacket w ereby said jacket will be filled with a stagnant body of air under the delivery pressure of the compressor.

11. A device'according to claim l, in which the conduit consists of relatively movable sections having overlapping ends iush at their outer surfaces, and a rin bridging the gap between the extremity o one section and a shoulder on the adjoining section.

In testimony WhereofI have hereunto set my hand.

CHRISTIAN LRENZEN.

der pressure to said chamber, a refractory conduit for conveying the hot gases from said combustion chamber to the turbine, and a jacket surrounding said conduit at a distance, said acket being connected only with the delivery side of said compressor, whereby said jacket will be filled with a stagnant body of air under the delivery pressure of the compressor.

" 6.l A device according to claim 5, in which the jacket contains a loose filling of reirac tory material.

7. In combination, a combustion chamber for producing hot gasesv under pressure, a refractoryV conduit for conveying the hot gases from said chamber, an annular refractory conduit connected with the delivery end of said rst-named conduit, and arranged to convey said gases to a place of use, a

jacket surrounding said conduits, and means for keeping said jacket filled with a stagnant gaseous fluid under pressure. Y

8. A device according to claim V7, in which the jacket, in addition to the stagnant gaseous iuid under pressure, containsY a loose illn ing of refractory material.

9. A device according to claim 7 in which the refractory annular conduit is provided at its outlet end, within said jacket, with a flange forming a tight joint with a stationary part.

10. In combination with a turbine, a refraci 

